Soudan Underground Laboratory Features Moderate depth (2100 mwe) augmented with active muon veto shield Existing infrastructure (power, water, networking, personnel, cranes, etc) and running experiments ESO and EPS in place External Sales Org = non-overheaded user invoicing mine labor, supplies, cryogens… Experimental Planning Statement = new experiments or screeners can be approved quickly (safety, materials, scheduling) Radon levels change seasonally: 300 – 700 Bq/m 3 Space for expansion, including enough for a 10 m dia x 6 m high water tank Mature Education and Outreach program with visitor’s center and tours

Soudan Underground Laboratory CDMS office New Clean Room CDMS Exp. MINOS Fully lined with an active muon veto Shielded hall Cu Electroform HPGe Screening (SOLO)

Diode-M 0.5kg in heavy use by XENON managed by Brown U (Gaitskell) Gator 1.2 kg Florida Start-up moved (Mar 2007) to Gran Sasso Gopher 1.2 kg Coming in January CDMS has many samples Gamma screening and isotope ID High Purity Germanium

M. Laubenstein: in screening sites around the world, the main backgrounds are internal to the detector and shielding itself

TASKS: Electroform and test a large vacuum copper cryostat structural integrity up to 2 atm, cooling capabilities, and electronic noise. Measure the amount of thorium-232 in the electroformed copper. PNNL measured < 1uBq/kg of 232 Th in the copper New Screener R&D to measure large quantities of Cu down to 0.1 uBq/kg square cross arm mandrel for cold finger + wires Endcap mandrel (16" diam x 14”) Funded via DOE Small Business Innovation Research grant Copper Electroforming (Reeves & Sons, LLC)

A 2090 mwe experimental hall (35’x40’x100’) lined with an active muon veto shield. Refurbished Soudan2 Muon Veto shield New gas system and controllers Pump jacks for tube repair New DAQ: Database of muons available to users: time stamp and location On Mezzanine: New Clean room Additional coincident tubes Structural support for lead cages Veto tube test stack Ceiling veto panels

An interactive graphical interface program retrieves the data remotely. Preliminary Angular distribution from new data compared to actual topological map of overburden S W N E S Currently studying muon angular distribution, multiplicity, shower fragments

What moves into this space? Medtronics soft memory error study is already there Dark Matter Ge Detector (December 2007) Neutron Multiplicity Counter: DUSEL R&D project (Case and UC Santa Barbara) Ultra-sensitive Screeners: Beta cage, XIA  counter, and Reeves Cu screener Still room for a large multi-purpose water tank Good match for the space and good usage of a pre-existing muon shield Muon veto shield 100 ft mezzanin e Clean room Beta Cage more muon tubes Clean room Water tank Ge Dark Matter Medtronics n multiplicity

Active Shielding for more effective depth 99.5% Muon Veto reduces n’s from shield by x 200 and n’s produced in rock by 4 Total n bkgd ~ 8 x n/day/kg Active Muon Veto outside tank reduces background from neutrons made in the shield

Active Shielding for more effective depth For Homestake depth, both curves drop by Without an active veto, 4850 mwe is 4 times worse than 2100 mwe Total n bkgd Active Muon Veto outside tank reduces background from neutrons made in the shield